We're so sorry to hear your Pronto doesn't appear to be taking a charge or only one indicator LED blinks continuously, showing no change after a significant period of time. It's possible it's defective, but it could also need to do a safety charge.
Due to shipping regulations, we have to ship our bulk battery shipment at a low charge level and, if they go for a long time without charging, they'll drop below the threshold that allows them to charge quickly and need to take around 72 hours to charge the first 1-2 times.
We realize this isn't ideal and are in the process of re-charging our batteries so you don't need to take this step in the future.
If your battery doesn't charge up after 72 hours (the bulk of the charge will happen in the last few hours), please send a message to [email protected] and we'd be happy to help troubleshoot or send a charged replacement your way. Please be sure to mention you've had them on the charger for over 72 hours.